Category: Maxillofacial Trauma

Introduction

Surgical practice routinely involves excision of body parts for treatment of pathologic lesions, producing defects of varying sizes. Defects may also be caused by other factors such as trauma, burns etc. Reconstruction of the lost body part is important in many respects. They include provision for cover, restoration of function and aesthetic rehabilitation.

A flap is defined as a tissue that is either transferred or transplanted with intact circulation. When vital structures are exposed in a complex wound or when reconstruction has significant functional or aesthetic consequences, a flap is generally required.

Reconstructive ladder

A defect may be managed by a wide variety of methods. The first objective in analysing a reconstructive problem is a correct diagnosis. The extent and type of missing tissue are assessed in order to formulate a plan for correction and reconstruction. In planning for management of defects of skin, mucous membrane and underlying structures, it would be prudent to follow what is known as the ‘reconstructive ladder’.

Small defects produced by burns or ulcerations may be allowed to epithelise primarily. Another option is closure by direct suturing when the defect is small enough and is otherwise suitable. When the defect is too large, the potential methods of reconstruction are the use of a free skin graft, a local skin flap, a distant skin flap, a composite flap or a free flap. Planning involves consideration of the simplest alternative followed progressively by the more complex, advancing up the ladder to the most complex. Progression from primary closure to skin grafts to local flaps to distant flaps and finally to microvascular free tissue transfers provides a set of options that can be applied to any reconstructive situation.

Allow wound to heal by secondary intention

Direct tissue closure

Skin graft

Local tissue transfers

Distant tissue transfers

Free tissue transfers.

General considerations

A skin flap in its basic form is a tongue of tissue consisting of the entire thickness of the skin plus a viable amount of the underlying subcutaneous tissue. It is transferred in order to reconstruct a primary defect and is inset into this defect. The transfer usually leaves a secondary defect, which is either closed by direct suture or covered by a skin graft.

An ideal flap should satisfy the following goals

provisions of a suitable colour match to the surrounding skin of the recipient bed.

assurance of a compatible thickness

retention, or provision of recovery, of clinically perceptible sensory innervation

attainment of sufficient laxity and tissue ablation such that mobile margins, as in an eyelid or lip, are spared retraction and deranged function

assurance that the resultant suture lines of either primary or secondary defects are restricted to anatomic units and fall within natural skin lines.

assurance that the reservoir from which the flap is mobilized is sufficiently lax to allow closure of the donor site resultant defect.

The flap may be raised from the tissues immediately adjoining, or very close to, the primary defect, in which case it is called a local/regional flap; alternatively it may involve the movement of tissue at a distance from the primary defect and is then called a distant flap.

When a local flap is transferred, movement takes place in the form of advancement, rotation, transposition or interpolation. Some flaps, at the time of transfer, are reattached to the body over their entire area, and the proximal end of such a flap, where it remains continuous with the adjacent skin, is referred to as its base.

With other flaps, the distal segment alone of the flap is inserted into the defect, its central segment and base remaining unattached. The base is then called the pedicle and the central segment is referred to as the bridge segment. These two, pedicle and bridge segment, act as the carrier and provide the channel for the blood supply of the distal segment. Once the distal segment establishes at the new site, which usually takes three weeks, the bridge segment is divided and either returned to its original site or discarded depending on the local situation. Insetting of the distal segment is then completed. In order to inset the distal segment, it is necessary to undercut its margin for a short distance.

While the pedicle of a flap usually consists of skin and subcutaneous tissue, it is occasionally reduced to its subcutaneous component, the distal segment alone, as an island flap, retaining skin as well as subcutaneous tissue.

When a distant flap is transferred, it is raised prior to transfer either single pedicled as a relatively long narrow tongue of tissue, or bipedicled as a strap of tissue with a pedicle at each end. Transfer to its destination is carried out in one of two ways –

If the flap is relatively near its ultimate destination, it may be swung on its pedicle, following division of one pedicle if it was bipedicled, and waltzed to its destination.

If it is at a greater distance from its destination, the flap is attached instead to a carrier, usually the wrist, on which it is conveyed to its destination.

Most local flaps have an axis around which they rotate or are transposed in the process of being transferred, and this is called the ‘pivot point’ of the flap. When it is at all possible, the bridge segment of any flap is ‘tubed’ in order to eliminate unnecessary raw surface and to reduce sepsis.

If it is felt that the blood supply of a flap would not be adequate for its survival if it were transferred straightaway, the circulation can be rendered more efficient by surgically outlining the flap. Such outlining is called ‘delay’. The term is also used for the procedure of surgically augmenting the blood supply of the flap.

According to McGregor and Morgan (1973), two distinct types of flaps can be distinguished according to their vascular characteristics and behaviour, each with a distinct geometry imposed by its vascular anatomy.

Axial pattern flaps

This type of flaps is constructed around a pre-existing anatomically recognized arteriovenous system. The vascular system running along its length makes it possible to construct a flap at least as long as the territory of its axial artery with minimal regard for consideration of its breadth. This factor also makes the flap more robust and better able to cope with any adverse circumstances that may arise.

Random pattern flaps

A random pattern flap has no pre-existing bias in its vascular pattern, and this lack places stringent limits on its dimensions, particularly in the ratio between its length and breadth. The degree of stringency placed on the dimensions of a random flap depends to a considerable extent on the richness of its subdermal vascular pattern.

Classification

There are a number of methods of classifying cutaneous flaps. Flaps may be classified by the arrangement of their blood supply (random vs. axial), by configuration (rhomboid, bilobed, elliptical etc.), location (local, regional and distant) ands by the method of transferring the flap (rotation, advancement, transposition etc.)

Local flaps

The local flap consists of tissue immediately adjoining the defect to be closed. It consists of skin and subcutaneous tissue. The local tissue may be dissected into a flap and mobilised to the defect by advancement, rotation, transposition or interpolation.

Advancement flaps

The advancement principle makes use of a linear configuration flap, raised and advanced to cover a rectangular primary defect which adjoins its distal end. Tissue transfer is achieved by moving the flap and its pedicle in a single vector. Advancement flaps may be categorized as single-pedicled, bipedicled or V-Y.

Single-pedicle flaps

Single-pedicle flaps are created by parallel incisions, which allow a sliding movement of the tissue in a single vector towards a defect. The movement is in one direction, and the flap advances directly on the defect. The flap is developed adjacent to the defect and one border of the defect becomes a border of the flap. Repair with an advancement flap involves both primary and secondary tissue movement. Complete undermining of the advancement flaps as well as of skin and soft tissue around the pedicle is important to enhance tissue movement. Bilateral advancement flaps are frequently combined to close various defects, resulting in ‘H’ or ‘T’ shaped repairs. It may also be used as an ‘island’ advancement flap.

It is virtually only in the face that the necessary skin laxity exists to allow advancement flaps to be used successfully. It works well in the repair of the defects of foreheads, helical rims, upper and lower lips, and medial cheek. Mucosal advancement flaps are also used for vermilion reconstruction.

The main drawback of this type of flaps is that a standing cutaneous deformity is created.

Bipedicle flaps

Bipedicle advancement flaps are used primarily for repair of large defects of the scalp. The flap is designed adjacent to the defect, and advanced to the defect at right angles to the linear axis of the flap. This leaves, apart from the dog-ear deformity, a secondary defect which must be repaired with a split skin graft. So, these flaps are seldom used now-a-days in the reconstruction of head and neck.

V-Y advancement flaps

In the case of V-Y advancement flaps, a V-shaped flap is pushed toward the defect. Thus the flap is moved into the recipient site without any wound closure tension. The secondary triangular donor defect is then repaired with wound closure tension by advancing the two edges of the remaining wound towards each other. Thus the wound closure suture line assumes a ‘Y’ shape, with the common limb of the ‘Y’ representing the suture line resulting from closure of the secondary defect.

V-Y advancement is useful when a structure or a region requires lengthening or release from a contracted state. It is particularly effective in lengthening the columella in the repair of cleft lip nasal deformities. It is also helpful in releasing contracted scars that are distorting adjacent structures as the eyelid or vermilion.

Pivotal flaps

There are three types of pivotal flaps – rotation, transposition and interpolation flaps. All pivotal flaps are moved towards the defect by rotating the base of the flap around a pivotal joint. The greater the degree of pivot, the shorter the effective length of the flap. This is because the pivotal point is fixed in position, and the base of the flap is restricted in pivoting around this point because of the development of redundant tissue at the base known as ‘standing cutaneous deformity (dog ear). Pivotal flaps must be designed to account for this reduction in effective length as they move around their point of pivot.

Rotation flaps

Rotation flaps are pivotal flaps that have a curvilinear configuration. Since the flap is being rotated to its destination, its ideal form is as the large arc of a circle of which the triangular primary defect is a small arc, with the flap and defect together making a half circle. They are designed immediately adjacent to the defect and are best used to close triangular defects. They are usually random in their vascularity but depending on the position of the base of the flap, they may be axial. Because the flap has a broad base, it vascularity tends to be reliable. Rotation flaps are useful in repairing medial cheek defects located near the naso-facial sulcus.

Large rotational flaps are particularly useful for reconstruction of sizable posterior cheek and upper neck defects. Incisions for the flaps are placed in a pre-auricular crease, and can extend for some distance along the anterior border of the trapezius muscle to facilitate rotation of upper cervical skin toward the area of the posterior cheek. A z-plasty at the base of the flap facilitates closure of the secondary defect. Chin reconstruction often can be readily accomplished with rotational flaps. Smaller rotational flaps may also be used for repair of defects located in the glabellar area. Scalp defects may be reconstructed with one or more flaps.

Transposition flaps

In contrast to rotation flaps, which have a curvilinear configuration, the transposition flaps have a straight linear axis. It can be designed in such a way that one border of the defect is also a border of the flap, or alternatively, with borders that are removed from the defect with only the base of the flap contiguous with the defect. In its ‘classic’ form, this flap is a rectangle, usually near square, which is raised and moved laterally into the primary defect, previously triangulated in preparation for it. Such a transfer leaves a secondary triangular defect which is at least equal in area to the primary defect.

Transposition is the most common method of moving local flaps into skin defects of the head and neck. They can be elevated in a multitude of sizes, shapes and orientation and usually are random cutaneous flaps, but may occasionally be compound. It is a reconstruction option for small and medium-sized defects. Its main advantage is that the flap can be designed some distance away from the defect, and the surgeon can select areas of skin elasticity and redundancy. The chief drawback is the secondary cosmetic deformity, but this can be hidden in hear-bearing areas.

Interpolation flaps

The interpolation flap, though it is a pivotal flap with a linear configuration, differs from transposition flaps in that its base is located at some distance from the defect. Thus the pedicle must pass over or under intervening tissue, and must subsequently be detached in a second procedure. This is the greatest disadvantage of this flap. On occasion, the pedicle can be de-epithelised or reduced to subcutaneous tissue only and brought under the intervening skin, to allow a single-stage repair.

A common interpolation flap is the mid-forehead flap, which includes the median and paramedian flap. They are highly effective in midface reconstruction because of their excellent vascularity and superb skin colour and texture match. Apart from nasal defects, defects of the medial canthal region, upper and lower eyelids, medial cheek, melolabial region and upper lip may be repaired with mid-forehead flaps. They are thin and viable flaps and can be easily contoured.

Rhomboid flaps

First described by Limberg (1966) and named after him (Limberg flap), the distinctive feature of the rhomboid flap is the precision of its design, which involved both the shape of the defect and the size and shape of the flap used to fill it. The defect is made in the form of a rhombus ( ) in such a way that its shorter diagonal equals the four sides in length.

The flap is outlined by extending the line of the shorter diagonal, for a distance equal to its length. From the extremity of this line, again equal in length to the shorter diagonal, is drawn at an angle 60˚ to it. In this way, a flap adjoining the defect is enclosed, with a size and shape similar to the rhomboid of the defect. Both the lines extended from the rhombus for flap design can be directed in either directions so that the flap can be placed in one or either side of the defect, with a further possibility of designing two flaps on each side, making four potential flaps in all. In practice, the side and direction of the flap are determined by the tissue available to be included in the flap.

The flap is raised and swung into the defect. This leaves a secondary defect, which is then closed by direct suture. The area where the rhomboid flap has its greatest value is the temple, between the eyebrows and the anterior hairline, and the appropriate direction is along the ‘crow’s foot’ wrinkle lines lateral to the outer canthus.

Bilobed flaps

In some situations, a defect which, in other respects is suitable for local flap reconstruction, is somewhat distant from an area of availability or lies at such an inappropriate angle that a suitable flap cannot be designed. Zimany in 1953 described a ‘bilobed’ flap for such situations.

The overall outline of the defect plus the flap is a ‘cloverleaf’ – one of the outer leaves being the defect, other two the bilobed flap, sharing the same pedicle. In the transfer, the central lobe of the leaf is rotated into the primary defect. This leaves a secondary defect which, in turn, is filled by the remaining cloverleaf. The tertiary defect so left is in an area of tissue availability, and so may be closed by direct sutures.

Hinged flaps

Cutaneous hinge flaps (trapdoor, turn-in, turn-out flaps) may be designed in a linear or curvilinear shape with the pedicle based on one border of the defect. The flap is dissected in the subcutaneous plane and turned over on to the defect like the page of a book. The epithelial surface of the flap is turned downward to provide internal lining of a facial defect that requires both external and internal lining surfaces. The exposed subcutaneous surface of the hinge flap is covered by a second flap.

The vascular supply of a hinge flap is derived from the soft-tissue border of the defect. And consequently they have limited and often restricted vascularity. The dissection should proceed in such a way that the base is thicker than the distal portion of the flap. Hinge flaps are commonly used for repair of full-thickness nasal defects and to close mature sinofacial and salivary fistulae.

Regional flaps

The regional flaps are local cutaneous flaps which involves transfer of tissue from areas adjacent to the defect. The commonly used regional flaps in head and neck include nasolabial flaps, forehead flaps, glabellar flap, tongue flaps etc.

Nasolabial flap

A nasolabial flap consists of a finger of tissue lying astride the nasolabial skin crease. It can be based above or below (superiorly or inferiorly based); and its main use is as a transposed flap to reconstruct defects of the side of the nose and the upper lip, occasionally the lower lip and oral cavity.

The nasolabial site is one of the most consistently available areas of lax skin. The area of skin which is used as the flap and its extension upwards and downwards varies considerably depending on the site, size and shape of the defect it is designed to cover. The flap is raised as a finger of tissue with its width made to correspond to that of the defect. Within limits, the length of the flap is not significant in vascular terms. The secondary defect is normally closed by direct suture.

The distribution of hair on the face and whether hair on the flap is desirable or undesirable will determine the ultimate the ultimate details of placing the flap. Used for defects of the nose, the superior pedicle is almost invariable. The lip and intra-oral defects may be repaired by either superiorly or inferiorly based flaps.

A nasolabial island flap may be designed, which bridges intact skin to reach the side of the nose. This is used to reconstruct the lower half of the side of the nose, occasionally the alar base and the margin, and rarely the adjoining upper lip.

Peri-alar rotation-advancement flap

This technique, described by Webster (1955), addresses the problem of asymmetry of the upper lip caused by direct closure of elliptical defects of alar bases. It involves excision of a crescent of the skin and subcutaneous tissue immediately lateral to the ala of the nose and mobilisation of the skin of the adjacent nasolabial area from the underlying cheek and lip musculature. The crescentic defect is then closed directly and the effect is to rotate and advance nasolabial skin into the lip defect to be closed without creating asymmetry.

Forehead flaps

The forehead flaps transfer the skin area from the forehead, most often to cover a defect of the middle third of the face. The tissue transferred can vary from a relatively small area to virtually the entire forehead. The pedicles generally make axial use of the superficial temporal, supraorbital and supratrochlear vessels, entering from the margins of the forehead. The secondary defect of a forehead flap is closed by direct suture when it is small enough; where it is too extensive, it is split-skin grafted.

Flaps raised from forehead are based either laterally on the temporal region, or inferiorly on the supraorbital region. The flap based laterally uses part or all of the breadth of skin between the ear and the outer end of the eyebrow. The flaps raised with an inferior pedicle vary considerably in design, but there are two basic designs – a straight relatively narrow finger like flap passing upwards from the glabellar region, and a ‘sickle’ shaped flap which rises in upward direction but curves down on the scalp to run vertically downwards on the opposite side of the forehead.

The temporal island flap, parented by the laterally based forehead flap, is occasionally used in the resurfacing of the malar region and also in reconstruction of the eyebrows.

Forehead flaps generally provide excellent contour and texture matches in the sites to which they are usually transferred.

Glabellar flap

The glabellar flap acts by transferring the skin from the glabellar region to cover defects of the side of the nose where it adjoins the medial canthus and the cheek immediately below the canthus. It is constructed on the hairless area between the eyebrows and the adjacent forehead, pivoting around the region of the superior orbital foramen on the opposite side from the defect, and incorporating a significant portion of the supraorbital and supratrochlear arteriovenous systems. The flap itself is triangular in outline with the apex pointing upwards on to the forehead. When it is rotated into the defect, it leaves a triangular secondary defect in the centre of the forehead, and this is closed by direct suture.

A glabellar island flap may be used to reconstruct the canthal area or the adjoining side of the nose and the cheek. Its parent flap is the finger variant of the supraorbital flap, rather than the classical glabellar flap. The subcutaneous pedicle pass from the island downwards towards the glabellar region.

Median glabellar flap

This rectangular flap (Rintala and Asko-Selvaara, 1969), long in relation to its width, is placed vertically in the glabellar region. With its base approximately 1 cm above the medial end of the eyebrows, its rectangle extends down over the bridge of the nose. It uses the principle of straight advancement to redeploy the glabellar area of skin availability, and can be used to cover square shaped defects of the upper third of the nasal skin in the midline. This method can be used only if the gap between the eyebrows is wide enough to allow a reasonably broad flap to be constructed.

Tongue flaps

Eiselberg used tongue flaps to repair oral defects in 1901. However, he gave credit to Gersuny at the end of the 19th century for the first use of a tongue flap to restore oral defects. Klopp and Schurter (1956), Bakamjian (1963) and Conley (1982) repopularised its use in the modern era.

The tongue flaps offer the advantage of adjacent and similar tissue for repair of intra-oral defects. An excellent axial and collateral circulation provides for flap viability. The lingual artery is the main vessel supplying the tongue. Anastomotic connections between the terminal lingual artery, the facial artery and the tonsillar branches of palatine artery are present. The branches that directly supply the tongue are the suprahyoid artery, the dorsalis lingual artery, the sublingual artery and the deep lingual artery. There are vascular arcades, which often perforate the midline of the tongue.

Dorsal based tongue flaps get most of their blood supply from an intact lingual artery. The rich collateral circulation of the tongue prevents tongue flap death as long as the base of the flap and its design allow for collateral circulation to develop.

A wide variety of tongue flap designs are possible, the common ones being anterior or posterior dorsal based lateral or midline flaps, posterior based lateral flap (Vaughn, 1983), posterior based bilateral lateral flaps, anterior based ventral flaps etc.

The common indications for tongue flaps include

reconstruction of intra-oral structures following cancer excision,

resurfacing of oral defects and

closure of palatal fistulae in cleft palate and acquired OAF.

Distant flaps

Deltopectoral flap

The deltopectoral flap is an axial pattern flap, first described by Bakamjian in 1965. It is composed of fascia, subcutaneous tissue and skin, and can be used for soft tissue reconstruction of mandible and maxilla.

The flap design is horizontal and rectangular with a rounded end over the shoulder. Based medially on the anterior chest wall, the flap on its upper border follows the clavicle and along the lower border, it runs just above the male nipple and not lower than the anterior axillary fold. In females, the base of the flap should include the first five ribs. The base of the medial portion of the flap must be 2 cm from the lateral sternal border to preserve the perforating vessels from the internal mammary artery, which supply blood to the flap. The perforators enter the flap through the first four intercostals spaces.

The fascia overlying the deltoid and pectoralis major muscles should be elevated with the flap by sharp dissection. Several branches of thoracoacromion artery will have to be ligated when elevating this flap. After appropriate planning and marking, the skin, subcutaneous tissue and the muscle fascia are sharply divided. The flap is elevated with skin hooks, and sharply dissected from the underlying muscles. It is then passed on to the defect and sutured in place.

The deltopectoral flap cannot be used for intra-oral reconstruction without creating an oral fistula. This is a controlled fistula and is necessary to preserve the blood supply to the flap. After the flap is sewn in place, it usually needs to be tubed.

The flap is divided 3 weeks later and the fistula closed. Waiting 6 weeks before dividing the pedicle ensures better survival of the flap. If the flap as designed is not long enough to fill the defect, it may be delayed to gain additional length.

The deltopectoral flap is useful for most reconstructive problems of head and neck, especially when a large amount of skin is required for coverage. It has been used in the repair of defects in the cervical oesophagus, hypopharynx, oropharynx, base of the tongue, mandible, maxilla and skin of cheek, chin and neck. In situations where both mucosal defects and skin defects are to be corrected, the combination of an appropriate myocutaneous flap for mucosal replacement, and the deltopectoral flap for external skin replacement works well. This flap may be used in most cases without having to reposition the patient.

The main disadvantage of this flap is the need to form an oral fistula and close it at a second operation. The donor defect is also a cosmetic problem. Another potential hazard is the rare occurrence of distal flap necrosis.

Cervical skin flaps

Flaps of varying size, shape, site and direction have been designed which make use if neck skin for reconstructive purposes. It is possible in theory to raise a flap from virtually any site on the neck and transpose it upwards to cover a defect of lower face or oral cavity. Being random in type, such flaps are restricted in their useful length.

Side of the neck

The flaps making use of the side of the neck are generally horizontally designed, based anteriorly or posteriorly. Because of their limited application, they are rarely used and have not been systematised in design.

Occipito-mastoid based flaps

From a base which extends form the midline and even beyond the occiput and event o the angle of the mandible, these flaps pass in a generally downward direction curving slightly laterally. Based on the downward extension, they may be ‘nape-of-the-neck’ flaps or sternocleidomastoid flaps.

‘Nape-of-the-neck’ flaps

This random pattern skin flap was first described by Mutter (1842). It makes use of the neck skin lying above the trapezius muscle. The flap can be raised pedicled on the occiput and extended downward as required to the approximate level of the spine of the scapula. Swung on the upper pedicle, such a flap can be used as a transposed flap to reconstruct the lower face and the submandibular region.

It is not generally considered safe to raise the ‘nape-of-the-neck’ flap and transfer it immediately because of the high incidence of necrosis. Prior delay is advisable and this makes it suitable for the already existing defect rather than the fresh post-excisional one.

Sternocleidomastoid flaps

This is a single-pedicled random pattern flap (Bakamjian and Littlewood, 1964), based on the skin overlying the upper insertion of the sternomastoid and running downwards along the line of the muscle. Pedicled above, it can be swung forward to be used both intra-orally and extra-orally.

Used as a skin flap, it has a bad reputation for necrosis (about 20%). Because of its vascular vulnerability, it is sometimes delayed before transfer. The incidence of necrosis can be greatly reduced by incorporating the underlying muscle as part of the transfer, thus making it a myocutaneous flap.

Apron flap

Described by Zovickian in 1958, this is a superiorly based flap which consists of skin from the submental region and front of the neck between the line of the carotids on either side. It is hinged along a line parallel to and just below the lower border of the mandible and is designed to be turned upwards along the inner side of the mandible to replace the mucosa of the anterior floor of the mouth and anterior part of lower alveolus. Problems resulting from the presence of beard skin led to its use as an island flap. This, combined with the compromise on vascularity following neck dissection, has made this flap unpopular.

Composite flaps

The composite flaps contain, apart from skin and subcutaneous tissue, underlying supportive tissue such as muscle, fascia or bone. Myocutaneous flaps with their excellent blood supply have proved to be very reliable in reconstruction following ablative surgery. In some instances, the underlying bone is pedicled on the muscle, thus making it an osteomyocutaneous flap

Muscle / myocutaneous flaps

Pectoralis Major Myocutaneous flap

The pectoralis major myocutaneous flap is the most useful flap for soft tissue reconstruction of bone and soft tissue defects of the mandible and maxilla secondary to cancer surgery. This flap was first described by Heuston and McConchie, who used it to reconstruct a chest wall defect in 1968. Ariyan (1979) demonstrated the vascular arrangement of the flap.

The pectoralis major muscle is a fan-shaped muscle on the anterior chest wall. It is bounded by the clavicle superiorly and the sternum medially. The lateral border forms the axillary fold. The superior fibres run parallel to the clavicle, and the inferior fibres run from the inferior border of the deltoid to the 5th and 6th ribs and lower sternum. The clavicular head of the muscle originates from the upper three ribs and the clavicle and inserts into the inter-tubercular groove of the humerus.

The pectoralis major muscle has two separate blood supplies. The thoracoacromial artery arises from the second portion of the axillary artery, and passes along the medial border of the pectoralis minor muscle and penetrates the clavipectoral fascia. It has 4 branches at this level. The pectoral branch is the largest, supplying the standard pectoralis major myocutaneous flap. The other blood supply to the muscle comes from the perforating branches of the internal mammary artery, which penetrates the muscle next to the sternum. The motor nerve to the upper half of the muscle is the lateral pectoral nerve, and that to the lower half is the medial pectoral nerve. Sensation is by the intercostals nerves.

The technique for flap elevation depends on the location of the defect. Most commonly defects of the head and neck require skin for lining the oral and maxillary cavity and bulk for filling bone and soft tissue defects. Currently two specific PMMC flaps are commonly used. These are the PMMC island flap and the PMMC paddle flap.

For raising an island flap, measurement is from clavicle to the inferior margin of the skin island, the measuring tape rotated to the defect to arrive at the appropriate length of the flap. The skin island may be placed on any part of the muscle as needed. The skin incision is carried down to the fascia of the pectoralis major muscle. Sutures are used to secure the skin island to the fascia. Then the entire muscle may be elevated, or it may be divided lateral to the island, leaving the lateral portion intact. The muscle is elevated primarily by blunt dissection off the ribs, care being taken not to enter the chest cavity. Medial to the island, the muscle is divided 2 cm lateral to the sternum to avoid injuring the internal mammary artery. The muscle is divided medially up to the clavicle. Laterally it is necessary to divide the humerus attachment. After the flap is elevated, the skin between the upper portion of the chest and neck is elevated and the flap passed under the skin to the defect. The neck incision is closed over the muscle, and the chest skin is mobilised and closed primarily in most of the cases.

In cases where the island flap is not long enough to cover the defect, a paddle flap may be useful. Another variant is the bilobular or ‘Gemini’ PMMC flap, in which two separate skin islands are raised with the muscle for simultaneous replacement of oral mucosa and overlying skin.

The pectoralis major myocutaneous flap and its variants are the flaps of choice for most defects in mandible and maxilla. It has also been used for the reconstruction of pharngoeophageal area, the base of the tongue, the anterior skull base, midface, total nose and orbital defects.

The PMMC flaps are very reliable in their survival chances. Very good functional and cosmetic results have been obtained using PMMC flaps along with dynamic fixation of the remaining mandible after partial resections. The disadvantages of this flap are also mainly cosmetic, the loss of muscle being very noticeable especially in thin patients. With 18 other muscles assisting shoulder motion, functional problems are rare.

Forehead flap

The forehead flap in its most reliable configuration is a myocutaneous flap, composed of the frontalis muscle extending from the hairline to the eyebrows with the overlying skin and subcutaneous tissue. It was introduced by Carpue in 1816. Blair (1941), Moore and Byars and McGregor (1963, 1964) have used this flap for lesions of the gingival mucosa, buccal mucosa and lateral pharyngeal wall. It may also be used to reconstruct defects of hard and soft palate.

The flap may be designed with a dual or single blood supply. It makes use of the superficial temporal artery and the posterior auricular artery, branches of external carotid artery. It may be used as a hemi-forehead flap or a total forehead flap depending on the size and location of the defect. The total forehead flap should include both the vessels.

The base of the total forehead flap extends from the lateral canthus of the eye to a point 2 cm posterior to the ear, to include the posterior auricular artery. The distal extremity is a transverse line at the level of the opposite lateral canthus. The base of the hemi-forehead flap extends from the lateral canthus at the eyebrow to the root of the superior helix of the ear and distally, it ends in the midline. The width of both types depends on the distance between the eyebrows and hairline.

Both the hemi-forehead and the forehead flaps are elevated at the level of the pericranium. The donor defect is covered with a split skin graft.

Various methods have been used for placing the flap into the oropharynx.

McGregor (1963) – the flap is rotated 180˚ laterally and entrance is gained into the oral cavity through a separate transverse incision.

Hoopes and Edgerton (1966) – the flap is rotated 180˚ medially and placed through a tunnel created at the base of the forehead pedicle that lies between the flap and the zygomatic arch.

Terz and Lawrence (1969) – the temporal fascia is incised and the flap folded medial to the zygoma to be transferred into the oral cavity.

The flap is hinged downwards and inserted into the oral cavity through the posterior part of the submandibular component of the neck dissection incision.

The advantages of forehead flaps are its close proximity to the orofacial regions, excellent blood supply and firmness of tissue. The main disadvantages are noticeable the donor site defect, the need to divide the pedicle to close the oral fistula art a second operation, and the frequent complication of bleeding. Flap necrosis, both major and minor, is an occasional problem.

Temporalis flap

The temporalis flap was introduced in 1898 by Golovine. The flap is useful

to obliterate skull base, maxillofacial and orbital defects.

to close cerebrospinal fluid leaks, to cover dural tears secondary to trauma or cancer operations

to reconstruct small intra-oral defects. The flap extends across the midline of the soft palate for repair of velum defects.

The temporalis muscle is a broad, fan-shaped bipennate muscle with two origins – deep one from the temporal fossa extending from the superior temporal line to infratemporal crest, and the superficial one from the deep temporal fascia. The insertion is onto the coronoid process and anterior ramus of the mandible. The deep temporal fascia invests the outer aspect of the mandible. The superficial temporal fascia lies on top of the deep fascia.

The blood supply of the deep temporal fascia is by the middle temporal vessel, a branch of superficial temporal artery. The temporalis muscle has a dual blood supply from the anterior and posterior deep temporal arteries. These vessels arise from the second portion of the internal maxillary artery.

The available length of the arc of rotation is estimated pre-operatively by palpating the superior extent of the muscle while the patient clenches his teeth. The incision is started in a skin crease anterior to the ear, and is extended superiorly toward the vertex, ending above the superior temporal line. The incision is carried down to the deep temporal fascia, and anterior and posterior flaps are developed above the deep fascia, until the entire muscle is exposed. Then the fascia is incised around the border of the muscle down to the calvarium. Elevation of the muscle is done in a subperiosteal plane.

The zygomatic arch may have to be divided to facilitate placement of the flap into the mouth. Additional mobility is gained by sectioning the coronoid process. A tunnel is created into the oral cavity by blunt dissection, and the flap is passed to the defect with the aid of traction sutures. Split skin grafts may be applied, but is not necessary.

The main advantage of the temporalis flap is its proximity to defects high in the oral cavity or on the face. Problem from loss of muscle function are minimal. It can support skin grafts, has a good arc of rotation, may be turned in different directions and is thin, providing for less bulky reconstruction.

The main disadvantage is the cosmetic deformity, though minimal, caused at the donor site. This may be corrected with autogenous or alloplastic materials, or camouflaged by hairstyle.

Platysma flap

The platysma flap was first used by Gersuny (1887) for reconstruction of a through-and-through cheek defect. In 1951, Edgerton described a lateral cervical island flap based on the platysma muscle for reconstruction of intra-oral defects. DesPrez and Kiehn (1959) reported the modified apron flap, which included the platysma muscle. In 1978, Futrell and colleagues reported the use of the platysma muscle as a true myocutaneous flap.

The platysma muscle lies deep to the subcutaneous tissue overlying the anterior and lateral aspect of the neck. Superficial cervical fascia separates it from sternocleidomastoid muscle, the great vessels of the neck and other underlying structures. The origin of the muscle is in the subcutaneous tissue just caudal to the clavicle and the acromion. Its insertion is just cephalad to the inferior border of the mandible. Laterally, it extends over part of the posterior triangle and sternocleidomastoid muscle. In the midline, it may merge at any point from the chin to the thyroid cartilage. Its function is to depress the lower lip.

The blood supply of the muscle and overlying skin was described by Hurwitz et al (1983) and Rabson et al (1985). The cervical skin is supplied by a random anastomosing network located superficial to the platysma. The principal vascular supply to the muscle is from branches of the facial artery. But it also receives rich blood supply from other vessels such as occipital, posterior auricular and superior thyroid arteries.

The flap may be raised on either a superiorly or inferiorly based pedicle. For use in the facial region, it must be raised as a superiorly based flap. If t is to be used in conjunction with neck dissection, it is elevated before the neck dissection is done. A skin island is designed on the inferior aspect of the muscle. Following an incision outlined to the platysma muscle, a supra-platysmal dissection is carried superiorly to the point of rotation. The incision through the inferior base of the skin island is carried deep to the platysma muscle and including the superficial cervical fascia. It is preferable to preserve as many blood vessels in the vicinity as possible.

The muscle is flipped 180˚ and brought through a tunnel into the mouth or is rotated and taken through a subcutaneous tunnel for coverage of extra-oral defects. The neck is closed primarily.

The primary use of this flap is in the reconstruction of intra-oral defects of the palate, buccal mucosa, tongue, floor of the mouth and pharynx; and extra-oral defects in the cheek and lower lip region. Advantages of this flap include its close proximity, and a minimal donor site defect which can be closed primarily. This thin, pliable flap causes negligible impairment of functions like deglutition, speech or prosthetic appliance use. It can be used for mild facial augmentation and reamination following facial nerve injury.

The greatest disadvantage of the platysma flap is that it is not reliable because of its unpredictable blood supply, which can cause flap loss. Another problem is the folding of the muscle which causes a bulge in the neck. Also, it cannot be used in regions where tissue bulk is required.

Sternocleidomastoid flaps

The sternocleidomastoid flap was introduced in 1909 by Jinau for facial reanimation. In 1949, Owens described a compound neck flap that included the muscle. This flap can be used as a muscle, myocutaneous or a myo-osseous flap.

The sternocleidomastoid muscle has two heads which at the origin attach to the manubrium sterni and the medial third of the clavicle. The insertion is to the mastoid process and lateral third of the superior nuchal line of the occipital bone. It divided the neck into anatomical anterior and posterior triangles.

The blood supply to the muscle is through three arteries. Superiorly a branch of the occipital artery enters the muscle below the mastoid tip. The middle branch is from the superior thyroid artery. The inferior third is supplied by a branch from the thyrocervical trunk. The dominant vessel is the occipital artery.

The incision is determined by the proposed use of the muscle. If a muscle flap is to be used alone, a vertical incision over the midportion of the muscle extending from its origin to insertion may be used. As an alternative, two horizontal incisions can be placed. The flap can then be elevated by tunneling through these incisions. A myocutaneous flap can be developed by basing it either superiorly or inferiorly with a skin island or skin pedicle attached to the muscle. In cases of simultaneous neck dissection, the McFee or hockey stick incisions can be modified to accommodate its elevation.

For superiorly based flaps, the flap is developed by elevating the skin and platysma from the underlying sternocleidomastoid muscle. The sternal and clavicular head are transected and the muscle is elevated by dissection between its deep surface and the deep cervical fascia. The lower branches of the vascular supply may be ligated without affecting the survival of the flap, according to Ariyan (1979). But Sasaki (1980) and Marx & McDonald (1985) recommend maintaining two of the supplying branches, by dissecting the middle branch (superior thyroid) back to its parent vessel.

The muscle is separated from the fascia, taking care to preserve the spinal accessory nerve. Arc of rotation may be restricted by the superior thyroid artery or the spinal accessory nerve. The muscle is then transposed and sutured in position, and the incision closed in layers over suction drains.

When a skin island is being taken, the incisions are carried down to the muscle fascia, the skin sutured to the underlying fascia, and the dissection proceeded as for the standard muscle flap. After the flap is rotated into position, the muscle is sutured to the subcutaneous tissues, and the skin island to the mucosa or skin as required. Because of variability in the axial blood flow, fluorescein may be used intra-operatively to determine the amount of viable skin. 1000 to 2000 mg of fluorescein is injected intravenously and the flaps are observed.

Extra-orally, the sternocleidomastoid flap can be used form the cheek to the neck area, and intra-orally, from the palatal region to the larynx. Other uses of the flap are to provide soft tissue augmentation after parotidectomy, for facial reanimation in 7th nerve injuries, to obliterate the dead space around a bone graft and to provide a vascularised muscle bed in patients with poor recipient tissues.

Advantages of the flap are the close proximity to recipient site, good colour match, adequate bulk and minimal donor site morbidity. The disadvantages include flat neck deformity, disruption of cutaneous nerve supply of the neck and unreliability of vascular supply of the flap. Potential limitations include the need to resect the muscle as part of neck dissection and obese people with short necks. Complications include muscle atrophy and flap necrosis.

Trapezius flaps

Flaps from the shoulder and back have a long history. Mutter described the trapezius flap in 1842, which was named after him. Zovickian popularised these flaps in 1957. Several designs of the trapezius myocutaneous flaps have been used because of its triple blood supply.

The trapezius is a flat and triangular muscle that covers the superior posterior part of the neck and shoulder. It originates from the nuchal line of the occipital bone and the spinous processes of C-7 through T-12. It courses laterally to insert on the lateral third of the clavicle, the acromion and the spine of the scapula. It overlies the semispinalis and splenius capitis in the neck, and both rhomboid muscles in the back.

The main blood supply of the trapezius muscle is by a branch of the thyrocervical trunk, the transverse cervical artery. At the border of the muscle, the vessel divides into an ascending and a descending branch, which permits separate flaps based on the lateral and vertical portions of the muscle. The upper portion of the muscle in the neck is supplied by the occipital artery. So this part of the muscle can be used as a separate myocutaneous flap. The muscle is also supplied by numerous deep perforating vessels from the intercostal system.

Three flap designs have been described – the upper trapezius flap, the lateral trapezius flap and the lower trapezius flap. The upper flap is the myocutaneous version of the standard nape-of-the-neck flap in which a strip of underlying trapezius is raised along with the skin (McCraw et al-1979). The flap in the form of an island can be rotated to allow a skin paddle to replace a mucosal defect.

The lateral trepezius flap (Bertotti, 1980, Guillamondegui & Larson, 1981) is based on the transverse cervical arterio-venous system and is raised from more or less the same skin area as the upper trepezius island myocutaneous flap. Its anterior border corresponds to approximately to the anterior margin of trepezius and from there it extends backwards and downwards in general the direction of the spine of the scapula. In order to be certain of including the vessels in the flap both the muscle element and the skin should extend above the point at which the transverse cervical vessels disappear deep to trepezius. The pivot point of the transfer is the medial end of its feeding arterio-venous system. The first step is to dissect the pedicle at its medial end. The island of skin with the underlying muscle is raised from levator scapulae. The flap can be used in conjunction either with a radical or a functional neck dissection.

The lower trapezius myocutaneous flap may be used as an island flap or as a solid flap. The vessels must be identified in the neck and traced to the anterior border of the muscle. The anterior incision for the skin island extends along the anterior border of the trapezius. The muscle and its blood supply are elevated from the underlying structures. An appropriate skin island is cut and the underlying muscle is incised with care. The pedicle is then isolated and traced to its origin at the thyrocervical trunk. The island, now attached only by its pedicle, is rotated into the defect and sutured into place.

The transverse cervical trapezius myocutaneous flap is useful for repairing defects within the oral cavity, hypopharynx or skin of the lower cheek and chin. For it to be considered, the blood supply must be preserved during the neck dissection. The horizontal (shoulder) fasciocutaneous flap is useful for coverage of neck.

The flap is a ready source of supple skin of uniform thickness without excessive muscle bulk, which lends itself to more contouring during reconstruction. The donor area is usually hairless and may be closed primarily in most cases. Scars in this area are not obvious.

The main disadvantages are the short pedicle available, limited arc of rotation and need for patient repositioning to use the flap. This flap cannot be used with a McFee incision. Injury or resection of the spinal accessory nerve causes significant and painful shoulder problems. Failure to heal donor defects is a dreaded complication.

Latissimus dorsi flap

The latissimus dorsi myocutaneous flap is one of the most useful and most reliable flaps that have been described. This flap was used by Tansini (1896) to cover a mastectomy defect. The use of this flap for reconstruction of head and neck defects was first described by Quillen et al in 1978.

The latissimus dorsi muscle extends from the tip of the scapula to the midline of the back posteriorly, and to the iliac crest inferiorly. The anterior border extends on an oblique line from the axilla to the midpoint of the iliac crest. The muscle is triangular and originates from the spinous processes of the lower six thoracic vertebrae, the spines of the lumbar and sacral vertebrae, posterior iliac crest, inferior angle of scapula and the last four ribs. The upper an anterolateral borders are free. The insertion is into the humerus in the intertubercular groove.

The thoracodorsal artery, the terminal branch of subscapular artery (which arises from the axillary artery), is the dominant vascular supply. Its vascular arrangement allows the muscle to be split into medial and lateral flaps. The secondary vascular source is from a few perforators from the posterior intercostals and lumbar vessels.

To reach defects in the head and neck region, the skin island must be placed on the anterolateral margin of the inferior half of the muscle. This area has the least number of perforating vessels. The size of the island conforms to the size of the defect, and the location of muscle paddle is distal enough to reach the defect by rotating the flap.

The initial incision is along the anterolateral border of the muscle. The skin island is outlined and the incision carried to the muscle. Then a skin incision is made connecting the island with the axilla along the proximal border of the muscle. Lateral and medial skin flaps are raised as needed to expose the muscle. The muscle is separated from the underlying bones. As the dissection proceeds upwards, the thoracodorsal pedicle is identified in the undersurface of the muscle.

Several different routes to the head and neck are available depending on the location of the defect. The flap may be tunneled over the pectoralis major and clavicle but under the overlying skin; or under the pectoralis major but over the clavicle. Care should be taken to protect the artery and the skin island. The flap is delivered to the defect and sutured in place. The skin defect on the back may be closed primarily or split-skin grafted. Drainage catheters are used under the back flap and also in the neck region.

The latissimus dorsi myocutaneous flap has been used to repair defects of the entire cheek, hemiface, oropharynx, mandible, segments of cervical oesophagus, posterior scalp, pharynx, etc. Its major advantage is the large amount of available skin and the wide arc of rotation. The blood supply is reliable, the muscle thick and the skin hairless. The main disadvantage is the need to reposition the patient during the operation. The donor site skin grafts occasionally fail to take.

Prior surgery in the axilla or radiation to the axilla makes the use of this flap unwise. Also, patients who have undergone thoracotomy with latissimus dorsi transection, are not candidates for this flap.

Osteomyocutaneous flaps

The osteomyocutaneous flaps consist of a segment of underlying bone pedicled on myocutaneous flaps, and are used for simultaneous soft and hard tissue reconstruction.

Sternocleidomastoid with clavicle/sternum

This flap was first described by Conley in 1972. He used all or part of clavicle and a part of sternum with sternocleidomastoid muscle. The main indications are for defects secondary to traumatic mandibular fractures, mandibular osteoradionecrosis and mandibular defects following cancer ablation.

The technique involves raising the contralateral flap with clavicle or sternum or both to reconstruct the mandible. The flap is raised preserving the occipital, posterior auricular and superior thyroid artery.

The main advantages are the provision for one stage reconstruction, and the rapid and technical ease of elevation of the flap. The disadvantages include loss of protection of great vessels, and the minimal donor site morbidity. The obvious limitation for its use is the presence of contralateral positive neck nodes in malignancy, in which case the sternocleidomastoid muscle will have to be excised.

Pectoralis major with rib

This flap was first developed by Ariyan et al in 1980. It is based on success with pectoralis myocutaneous flap and good periosteal supply to ribs form the pectoralis muscle.

The pectoralis muscle has three heads of origin the clavicular head from anteromedial clavicle, sternocostal head from anterior sternum and six upper ribs and abdominal head is variable from the external oblique muscle. It is inserted into the lateral lip of the humerus and deep fascia of the arm.

Vascularised upper six ribs based on the periosteal blood supply can be harvested along with pectoralis flap for maxillary and mandibular reconstruction. Usually 5th or 6th ribs are harvested with the muscle flap.

This flap combines the advantages of the versatile and durable myocutaneous flap and the presence of osseous tissue for bone reconstruction. Large skin island with soft tissue bulk is available for oral and facial reconstruction. Its long pedicle allows it to be mobilised to greater distance.

The disadvantages include poor bone stock for mandibular reconstruction, limited vascular supply to the bone, chance of pneumothorax, poor contour stability and limited dental restoration potential and the significant donor site cosmetic defect.

Trapezius with spine of scapula

Trapezius osteomyocutaneous flap for mandibular reconstruction was first described by Panje and Cutting in 1980. Here, the spine of scapula is harvested along with trapezius muscle for oromandibular reconstruction.

It has the advantages of a versatile and durable myocutaneous pedicle in the muscular part, with a dependable vascular supply. Other advantages are the location of the flap close to the operating site, low morbidity of donor site bone defects less than 12 cm, provision for large skin island and improved bone stack in comparison to rib with pectoralis flap.

Disadvantages include the requirement for repositioning during the procedure for flap harvest, inadequate bone stock for defects larger than 12 cm, limited manipulation of bone relative to soft tissues and the frequent complication of shoulder morbidity due to acromion damage and denervation.

Latissimus dorsi with rib / iliac crest

Maruyama et al (1985) described the use of this flap with rib for reconstruction of a complete hemimandibulactomy defect secondary to osteoradionecrosis. The vascular supply of the rib graft comprised of perforating branches from the posterior intercostal artery and the periosteal supply from the thoracodorsal artery. Follow-up bone graft biopsy at 3 months revealed viable bone.

An innovative latissimus dorsi myocutaneous–iliac crest bone flap was described by Magi et al (1986). A segment of iliac crest was transplanted beneath the muscle 2 months before raising the flap. The composite flap was then used for mandibular reconstruction. The results were disappointing in their two patients.

Temporalis with calvarium

As early as 1890, Konig and Muller reported the clinical applications of calvarial bone transfers with osteocutaneous flaps. Watson-Jones in 1933 transferred calvarial bone on periosteal pedicles to repair depressed skull fractures. Conley (1972) designed an osteomuscular flap consisting of temporalis muscle and clavarial bone. The bone-muscle-fascial-periosteal flap was developed by McCarthy and Zide in 1984.

The temporalis flap has an excellent arc of rotation about the coronoid process. It can be rotated to reconstruct the defects of orbit, oral cavity and also of face.

The advantages of this flap include minimal morbidity of the donor site and large volume of bone with a curvature. It is claimed that the viability of the membranous bone is superior to the endochondral bone.

Free flaps

Microvascular techniques for anastomosis of small vessels allow the transfer of skin flaps from distant sites. Free vascularised tissue transfer is a major advance in maxillofacial reconstruction by providing tissue with inherent ability to heal. These flaps are particularly useful in cases where adequate tissue for reconstruction is not available in the vicinity of the defect, and where the recipient bed is not vascular enough to facilitate the take of an ordinary flap.

An artery and vein of adequate size and in proximity to the defect should be chosen for microvascular anastomosis. It is usually possible to choose vessels with adequate pedicle length for donor vessels to reach. Delicate handling of the vessels is essential to prevent damage to the intima. The recipient vessels may be sutured end-to-end or end-to-side to the donor vessels. Branches of the external carotid artery and internal jugular vein may be used as recipient vessels.

Jejunum

The small intestine has been used for reconstruction of cervical esophagus to provide a reconstructive pharyngeal conduit following pharyngolaryngectomy and for resurfacing the oral cavity defects.

A segment of proximal jejunum is harvested along with mesenteric vasculature, which is capable of providing a single arterial and venous pedicle suitable for anastomosis. After the harvest of jejunum the continuity of the intestine is restored.

The advantages of this flap for intra-oral reconstruction is that the transferred tissue has a mucosal surface which secrete mucous and that the vascular pedicle is of adequate caliber for anastomosis.

The disadvantages of this flap are that it requires abdominal operation and the operating period is prolonged.

Groin flap

This was the first free tissue transfer performed with micro-vascular technique. First described by Wood in 1863 and reevaluated by McGregor and Morgan in 1973 as an axial pattern flap. The skin overlying the Iliac crest and ilium are perfused by arteries which anastomose in the vicinity of the anterior superior iliac spine, the superficial and deep circumflex arteries and the superior gluteal artery.

The standard groin flap is based on the superficial circumflex iliac artery, usually a branch of femoral artery. Venous drainage is by a superficial and deep system of veins. Large area of tissue meassauring up to 24 by 16 cm can be successfully transferred. The donor defect is minimal. It can also be used as a de-epithelised flat flap for repair of soft tissue defects.

The disadvantages are a variable pattern of vascularity, short vascular pedicle and the excess bulk of the groin.

Lateral arm

The lateral arm provides a free flap based on the posterior radial collateral artery, which is a direct continuation of the profunda branchii. The flap is thin and pliable and consists of fascia and skin. The posterior cutaneous nerve of the arm accompanies the artery and can be transferred with the flap.

Several branches from the artery provide a periosteal blood supply to the humerus and can allow harvesting of a small segment of vascularised bone.

Latissimus dorsi

Described by Maxwell (1978), the flap consists of latissimus dorsi muscle and its overlying skin paddle. The dominant vascular pedicle is the thoracodorsal artery, arising from the subscapular artery (branch of axillary artery). The subscapular artery and its branches offer a variety of flaps suited for free tissue transfer. Venous drainage is by venae comitantes, which accompany the thoracodorsal and axillary arteries.

The flap offers a large amount of tissue with a good quality skin element, thus making it useful to fill large and full thickness head and neck defects. It is very reliable and is easy to use. The disadvantages are the bulk, risk of seroma formation and functional incapacitation in certain occupation groups (athletes and tennis players). The muscle bulk settles slowly over time as the denervated muscle shrinks.

Rectus abdominis

The rectus abdominis muscle can be transferred either as a muscle flap or as a myocutaneous flap. The muscle is supplied by the superior and inferior epigastric vessels. The larger pedicle is the inferior epigastric, which forms the basis of the rectus abdominis free flap.

This flap is very useful in cases where an extensive area of soft tissue cover is required. Alternatively, it is possible to take a small amount of muscle that contains two or three perforators, which supply a large area of skin. It has a consistent, reliable, long vascular pedicle with vessels that are easily dissected.

The removal of the muscle causes some abdominal weakness, and ventral herniation is frequent. The flap is often too bulky.

Dorsalis pedis

First described by O’Brics and Shanmughan in 1973, this fasciocutaneous flap transfers skin, superficial fascia from the dorsum of the foot using as its vascular basis the dorsalis pedis artery and the superficial veins, which pass proximally into the long saphenous system. The vascular pedicle of this flap can be dissected from the leg to a length of at least 10 to 15 cm. If additional venous drainage is required, the saphenous vein may be included in the flap.

It has been used both to provide skin cover and an intra-oral lining. Second metatarsal bone can be harvested along with the flap for mandibular and temporomandibular reconstruction.

Iliac crest – composite groin flap

The iliac bone along with its overlying skin paddle can be harvested as a free flap based on either the superficial or deep circumflex iliac arteries. This flap was first described for mandibular reconstruction by Daniel (1978). Taylor et al (1983) showed the superiority of the deep circumflex iliac arteries. The segmental nature of the vessels supplying the iliac crest allows maintenance of viability with multiple osteotomies. The deep circumflex iliac artery arises from the external iliac artery just above the inguinal ligament. The venous drainage of the flap consists of two venae comitantes which may unite to form a single trunk.

The flap provides an abundance of well-vascularised iliac bone (corticocancellous), which can be used to adequately reconstruct large mandibular defects including hemimandibular or even total mandibular defects if bilateral flaps are used. The donor defect is minimal.

The chief disadvantages are the risks of necrosis of the skin segment and abdominal wall herniation. The dissection is tedious.

Radial fore-arm flap

The radial forearm free flap, described by Soutar (1983), is a fasciocutaneous flap based on the radial artery. The venous drainage is dual; the paired venae comitantes accompanying the radial artery and the subcutaneous veins. These two systems communicate and either can be used to provide adequate venous drainage.

The entire fascia and skin of the volar aspect of the forearm can be used for microvascular transfer. The periosteum of the radius is supplied by a rich network of vessels from the radial artery, and a vascularised segment of radius lying between the insertion of the pronator teres and the radial styloid may be transferred with the flap.

The flap is extremely reliable, has a constant anatomy, and has large diameter vessels. A large amount of thin, pliable skin may be harvested. The blood supply to the bone and skin arises from a different system of perforators, thus permitting multiple osteotomies without compromising skin viability. Furthermore, the segmental blood supply preserves vascularity of all segments. This flap is most useful in mucosal defects of the floor of the mouth and anterior mandibular defects in combination with floor of the mouth defects.

The main disadvantage is the need to interrupt the radial artery and the resultant compromise to vascularity of the hand. The amount of bone available for use is limited to 10 or 11 cm in length. This limits its use to small defects.

Scapular / parascapular flap

The scapular and parascapular free flaps are based on transverse and descending branches, respectively, of the circumflex scapular artery, which is the largest branch of axillary artery. Each artery is usually accompanied by two venae comitantes.

The flaps are of fasciocutaneous type, though variable amounts of bone or muscle (serratus anterior) can be included in selected cases. Large cutaneous paddles based on either of the arteries may be raised. The descending branch provides multiple segmental vessels to the periosteum of the lateral border of scapula, allowing a vascularised segment of bone to be harvested.

The flap is relatively thin, the anatomy reliable, and a large area is available for transfer. It also allows a second large myocutaneous area based on thoracodorsal vessels to be harvested. The donor site can be closed primarily and the flap hidden in clothing.

The chief disadvantage is the need to reposition the patient. The dermis of the back is thick, and the scar tends to widen in course of time.

Fibula free flap

Introduced in 1975 by Taylor et al, the free fibula flap was one of the earliest osseous free flaps with extensive application in long bone reconstruction. In 1983, Chen and Yan described the vascular supply of free fibular osteocutaneous flap. Hidalgo (1992) reported the first application in mandibular reconstruction. Hayden (1992) described the nerve supply to the cutaneous paddle and advocated a neurosensory potential. He also demonstrated successful primary osseointegration with titanium implants in the fibula.

A long segment of fibula can be harvested as a free flap based on the peroneal artery. The blood supply is rich, consisting of both medullary and periosteal vessels, which allows osteotomies without jeopardising viability. The branches of the common peroneal nerve, the lateral cutaneous nerve of the calf or the sural communicating nerve may be harvested with the flap to provide a neurosensitised skin paddle.

The dissection is straightforward and provides vessels of moderate size. The bone is strong and can even be folded on itself to provide a double strut. Donor site morbidity is unusual as long as the distal 5 to 6 cm of fibula is left for ankle support.

Reconstruction of specific regions

The different techniques used in reconstruction of head and neck are broadly classified as follows: –

Type IV Total maxillectomy and palatectomy; orbital support remains intact

Type V Total maxillectomy and palatectomy with loss of orbital support or eye.

Midface defects produce significant functional and aesthetic consequences. Feeding and speech can be a problem. Oro-antral fistula and velopharyngeal incompetence can develop. Resection of Lockwood’s ligament may result in enophthalmos and orbital dystopia.

Type I defects

Patients with type I defects suffer from variable loss of soft tissues of cheek and lips. Bony framework is not affected. Palate and orbital floor remain intact.

If the defect is small and the surrounding tissue lax, primary closure may be possible. Small rhomboid flaps or subcutaneous pedicled flaps are used for superficial midface defects. Tissue expansion has been used successfully for superficial defects of cheek. This technique affords excellent colour and texture match with least amount of scar tissue formed.

For larger defects, regional or distant flaps like pectoralis major, deltopectoral, latissimus dorsi, temporalis and forehead flaps have been used with success.

Type II & III defects

The traditional method of reconstructing these defects is by skin-grafting the internal cavity and the placement of a maxillofacial prosthesis. The prosthesis usually serves as a denture and a palatal obturator, closing the oro-antral fistula and providing projection of midface. An adequate residual palatal arch and surrounding soft tissues are required to support the prosthesis. As the size of the defect increases, problems with stability often are exacerbated especially if the prosthesis must function as a support for orbital structures or reconstruct a missing cutaneous segment.

Some limited maxillectomy defects may be reconstructed using autogenous tissue. Choung et al described the use of ipsilateral or bilateral temporalis muscle flaps. Calvarial bone may be included in the flap, making it a myo-osseous flap. The zygomatic arch may be cut anteriorly and posteriorly so that the muscle is mobilised to its insertion on the coronoid process. The composite flap is passed into the oral cavity and sutured to the remaining septum or palate.

Type IV defects

Individuals with extensive defects are best served by reconstruction with regional or distant flaps to obturate palatal defects, to provide complete soft tissue coverage and to aid in retention of a prosthesis. The reconstuctive goal is to provide a healed wound, separation of oral and nasal cavities, support for intracranial contents and obliteration of maxillectomy defects.

A variety of pedicled regional flaps have been advocated for midface resurfacing. They include the deltopectoral flap, pectoralis major myocutaneous flap, forehead flap etc.

Each donor site has its own advantages and disadvantages. The rectus abdominis flap allows a two-team approach, thus reducing operating time. Both the latissimus dorsi and scapular flaps require a change in the patient position, but they provide long vascular pedicles and large volumes of tissue. By de-epithelising intervening segments of dermis between cutaneous paddles, the palatal, maxillary and orbital components of the defects may be simultaneously reconstructed.

Isolated soft tissue repair without bony reconstruction tends to lose midfacial projection and result in sagging. Coleman and Sandham noted that by preserving the angular artery to the tip of scapula, vascularised bone could be harvested along with the scapular flaps. This helps in closure of massive midface defects. The muscular component helps in the closure of dead space of maxillary sinus. The cutaneous portion is used to resurface face and palate.

Type V defects

When orbital floor and Lockwood’s suspensory ligament are resected, reconstruction should obliterate the orbital cavity and restore facial contour.

Ilankovan and Jackson described the split thickness vascularised calvarial bone either pedicled on the temporalis muscle or with a free flap based on superficial temporal artery, to reconstruct the floor of the orbit.

The temporoparietal fascial flaps have been used for orbital and eyelid reconstruction. The free vascularised forearm flaps have been used to reconstruct the orbital floor and provide overlying soft tissue.

In extensive maxillectomy defects, soft and hard tissue requirements are massive, and free tissue transfer is preferred. It offers the advantage of one-stage reconstruction without the constraint of fixed point of rotation observed in regional flaps.

Reconstruction of the lip

The successful reconstruction of the lower lip must meet some criteria.

The reconstructed lip should be sensate.

Retain sphincter or muscle function.

Oppose vermilion to vermilion of the upper lip in a watertight continent seal.

Allow sufficient space for food, dentures and so on.

Acceptable aesthetic appearance.

Defect of up to one third of the lip can be closed primarily. Larger defects require tissue transfer, and the preferred donor site is adjacent cheek or upper lip.

Defect of 30% to 50%: –

In moderate-sized defects, reconstructive techniques that use lip tissue will yield an excellent result. Transfer of upper lip tissue (lip switch) pedicled on the labial artery (Abbè technique), preserving the oral commissure, or rotated around the commissure by the Estlander method can be accomplished.

Another method is Karapandzic technique of advancement rotation of segments of skin, orbicularis and mucosa – after division of other supporting muscles. This procedure redistributes remaining lip, yet preserves the motor and sensory function. The principal disadvantage has been the relative microstomia and the necessity of extensive circumoral incision and dissection.

Defects of 65% to 80%: –

A widely used technique is the advancement of the cheek tissue by the Webster- Bernard approach. Initial results are good; the continued chronic tension of the closure has culminated in a tight lower lip that functioned poorly.

A more satisfactory procedure for defects of this magnitude has been the Karapandzic lip rotation, although a microstomia is inevitable. Denture construction should be modified here.

The Karapandzic approach essentially is dissection of the remaining lower lip segment, modiolus (bilateral) and lateral upper lip tissue in the neurovascular pedicles and advancement of these components to reconstruct the lower lip deficiency. The method requires incisions extended laterally and transversely in adjacent cheek tissue, curving upward into the nasolabial folds and into the lateral upper lip toward the alar base. Once skin incisions are made, the residual depressions and elevations are divided, beneath which lie both the facial nerve and artery branches to be preserved. Similar incisions need to be made in the mucosa at the labial sulcus, extending into the labial mucosa.

After mobilization of the segments, closure of donor site defect in the cheek is done in a V to Y fashion. Microstomia produced can be corrected later with a lip-switch procedure.

Total resection of the lip: – (Karapandzic approach)

A massive resection of the lip, chin and mandible must be reconstructed with distant flaps and requires reconstruction of the lower lip as a separate unit. The transfer of composite flaps of skin and bone revascularised and the result allows for institution of radiotherapy in the early post postoperative period.

Reconstruction of the lip and chin as a single unit can be accomplished with a radial forearm flap, incorporating a plantaris tendon as a vascularised unit to provide support. The tendon is sutured into either modiolus (if still present). The provision of sensation to the reconstruction by suturing the antebrachial cutaneous nerve of the flap into the stump of the mental nerve has been included.

To effectively reconstruct the lower lip, one must provide not only skin and mucosa, but also functioning mimetic muscle. Dissection of a platysma myocutaneous flap with an extended muscle pedicle to include the cervical branches of the facial nerve would empower the muscle component. Bilateral flaps would also provide sufficient tissue for mucosa reconstruction.

Another use of a full thickness inferiorly based nasolabial flap or bilateral flaps as needed for lower lip reconstruction.

Conclusions

Defects of the head and neck region resulting from severe trauma and ablative procedures for neoplasms, and those associated with congenital deformities, can be functionally and aesthetically debilitating. The primary objective of the reconstructive surgeon is to restore a level of form and function that provides the closest approximation of the patient’s pre-disease state.

Reconstructive options for patients with large defects have significantly progressed over the last century. The early primary closure techniques with their poor aesthetic results have now been replaced by improved surgical techniques, including composite tissue transfer. Free tissue transfer has now enabled the surgeon to reliably reconstruct the defects in areas of inadequate tissue availability and regions of vascular compromised. Different types of flaps, if used judiciously and carefully, allows reliable aesthetic and functional reconstruction in specific situations.